Many vehicles are provided with a power take off (PTO) drive. The engines for these vehicles are typically fuel throttle controlled, preferably electronically, and are generally connected to an electronic data link of the type defined in, for example. SAE J1922 and/or SAE J1939 protocol. The electronically controlled engine is usually provided with its own electronic control unit (ECU). An input shaft brake may be incorporated that provides quicker manual upshifting as is well known in the prior art. It is understood that a data link or databus complying with SAE J1922, SAE J1939, CAN and/or ISO 11898 protocols, or similar protocols, carries information indicative of engine torque, engine speed, transmission output shaft speed. PTO speed, and brake information.
Fully or partially automated transmission systems wherein a microprocessor-based electronic control unit (ECU) receives input signals indicative of various system operating conditions and processes same according to logic rules to issue command output signals to one or more system actuators are known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,361,060; 4,593,580; 4,595,986; 4,850,236; 5,435,212; 5,582,069; 5,582,558; 5,620,392; 5,651,292; 5,679,096; 5,682,790 and 5,735,771; the disclosures of which are incorporated herein by reference in their entirety.
Compound manually shifted mechanical transmissions of the range, splitter and/or combined range/splitter type are in wide use in heavy-duty vehicles and are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,754,665; 5,272,929; 5,370,013 and 5,390,561, 5,546,823; 5,609,062 and 5,642,643, the disclosures of which are incorporated herein by reference in their entirety. Typically, such transmissions include a main section shifted directly or remotely by a manual shift lever and one or more auxiliary sections connected in series therewith. The auxiliary sections most often were shifted by a slave actuator, usually pneumatically, hydraulically, mechanically and/or electrically operated, in response to manual operation of one or more master switches. Shift controls for such systems may be seen by reference to U.S. Pat. Nos. 4,455,883; 4,550,627; 4,899,607; 4,920,815; 4,974,468; 5,000,060; 5,272,931; 5,281,902; 5,222,404; and 6,463,893, the disclosures of which are incorporated herein by reference in their entirety. U.S. Pat. No. 4,527,446, the disclosure of which is incorporated herein by reference in its entirety, discloses a fully automated, blocked-type transmission wherein the main section is automatically shifted to main section neutral during each shift.
PTO systems for vehicle drivetrains may be seen by reference to U.S. Pat. Nos. 5,070,982 and 6,497,313, and typically include a PTO synchronizing clutch, or hot-shift clutch, to synchronize and engage PTO input and output components, such as shafts, gears, or clutch members. Some systems include a PTO where some components may be damaged if operated during maximum engine rotational speed. In these applications, when the engine is operated at an undesirable speed, the PTO clutch may be used for disengaging the PTO driven device until the engine speed is reduced.